BPI-PicoW-S3 使用双轴摇杆[CircuitPython]

Mu编辑器

BPI-Pico-S3 与 Raspberry Pi Pico 板尺寸相同，搭载ESP32S3芯片，8M flash，4层PCB，电镀半孔工艺，陶瓷天线，支持 2.4 GHz Wi-Fi 和 Bluetooth® LE 双模无线通信，是一款专为物联网开发和Maker DIY设计的开发板。

出厂内置 tinyUF2 + CircuitPython，推荐使用Mu编辑器上手CircuitPython开发。

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硬件接口示意图

使用双轴摇杆

这是一个常见的双轴XY摇杆模块，使用了两个电位器最为其核心器件，通过芯片的ADC 模/数转换器读取它们各自的电压数值，即可将读数转化为其在XY坐标轴上的位置。

双轴摇杆	BPI-PicoW-S3
GND	GND
+5V	3V3
VRx	GP26_A0
VRY	GP27_A1

在CircuitPython中提供的ADC精度是16bit，即最大值的16进制表达为 FFFF，10进制表达为 65535，对应的电压量程为0mv ~ 3300mv。BPI-PicoW-S3所使用的EPS32S3芯片实际ADC电压量程为0mv ~ 3100mv，所以实际应用时仅能测量到3100mv。
基础ADC读数，读取两个电位器的数值，转换为电压数值。

import board,analogio,time

x_axis_pin = analogio.AnalogIn(board.A0)
y_axis_pin = analogio.AnalogIn(board.A1)

while True:
    x_axis = x_axis_pin.value
    y_axis = y_axis_pin.value
    # print((x_axis,y_axis))
    x_value = x_axis / 65535 * 3300
    y_value = y_axis / 65535 * 3300
    print("{0}mv,{1}mv".format(x_value,y_value))
    time.sleep(0.1)

在Mu编辑器中，点击Plotter图标即可显示绘图仪，可以实时将REPL输出的数值显示为与时间相关的折线图。

以下程序可实现校准坐标零点的功能。开始运行的前五秒，请静止摇杆等待获取零点数值。

import board,analogio,time

x_axis_pin = analogio.AnalogIn(board.A0)
y_axis_pin = analogio.AnalogIn(board.A1)

def get_zero(times =500, sleep = 0.01):
    x_total = 0
    y_total = 0
    for i in range (times):
        x_axis = x_axis_pin.value
        y_axis = y_axis_pin.value
        x_total += x_axis
        y_total += y_axis
        time.sleep(sleep)
    x_zero = x_total // times
    y_zero = y_total // times
    return (x_zero,y_zero)

zero = get_zero(times =500, sleep = 0.01)
print(zero)

while True:
    x_axis = x_axis_pin.value - zero[0]
    y_axis = y_axis_pin.value - zero[1]
    print((x_axis,y_axis))
    time.sleep(0.1)

以下程序可获取摇杆方向，这是双轴摇杆最常见的应用。

import board,analogio,time

x_axis_pin = analogio.AnalogIn(board.A0)
y_axis_pin = analogio.AnalogIn(board.A1)

direction_list = ["East","Southeast","South","Southwest","West","Northwest","North","Northeast","Centre"]

def get_zero(times =500, sleep = 0.01):
    x_total = 0
    y_total = 0
    for i in range (times):
        x_axis = x_axis_pin.value
        y_axis = y_axis_pin.value
        x_total += x_axis
        y_total += y_axis
        time.sleep(sleep)
    x_zero = x_total // times
    y_zero = y_total // times
    return (x_zero,y_zero)

def get_direction(zero = (32767,32767)):
    x_axis = x_axis_pin.value - zero[0]
    y_axis = y_axis_pin.value - zero[1]
    if x_axis >= 10000 and -10000 < y_axis < 10000:
        return direction_list[0]
    elif x_axis >= 10000 and y_axis <= -10000:
        return direction_list[1]
    elif -10000 < x_axis < 10000 and y_axis <= -10000:
        return direction_list[2]
    elif x_axis <= -10000 and y_axis <= -10000:
        return direction_list[3]
    elif x_axis <= -10000 and -10000 < y_axis < 10000:
        return direction_list[4]
    elif x_axis <= -10000 and y_axis >= 10000:
        return direction_list[5]
    elif -10000 < x_axis < 10000 and y_axis >= 10000:
        return direction_list[6]
    elif x_axis >=10000 and y_axis >= 10000:
        return direction_list[7]
    else :
        return direction_list[8]

zero = get_zero(times =50, sleep = 0.01)
print(zero)

while True:
    x_axis = x_axis_pin.value - zero[0]
    y_axis = y_axis_pin.value - zero[1]
    print((x_axis,y_axis))
    print(get_direction(zero = zero))
    time.sleep(0.1)

以下程序可设置坐标精度等级，计算每级跨度，可以按需求消除抖动，增强数据的实用性。

import board,analogio,time

x_axis_pin = analogio.AnalogIn(board.A0)
y_axis_pin = analogio.AnalogIn(board.A1)

def get_zero(times =500, sleep = 0.01):
    x_total = 0
    y_total = 0
    for i in range (times):
        x_axis = x_axis_pin.value
        y_axis = y_axis_pin.value
        x_total += x_axis
        y_total += y_axis
        time.sleep(sleep)
    x_zero = x_total // times
    y_zero = y_total // times
    return (x_zero,y_zero)

def get_extremum(times =500, sleep = 0.01):
    x_list = []
    y_list = []
    for i in range (times):
        x_axis = x_axis_pin.value
        y_axis = y_axis_pin.value
        x_list.append(x_axis)
        y_list.append(y_axis)
        time.sleep(sleep)
    x_extremum = (min(x_list),max(x_list))
    y_extremum = (min(y_list),max(y_list))
    return (x_extremum,y_extremum)
    
def get_spacing(level = 16 , zero =(32767,32767) ,x_extremum = (0,65535),y_extremum = (0,65535)):
    x_temp_1 = (zero[0] - x_extremum[0]) // level
    x_temp_2 = (x_extremum[1] - zero[0] ) // level
    y_temp_1 = (zero[1] - y_extremum[0]) // level
    y_temp_2 = (y_extremum[1] - zero[1] ) // level
    x_spacing = (x_temp_1,x_temp_2)
    y_spacing = (y_temp_1,y_temp_2)
    return (x_spacing,y_spacing)

def get_coordinates(zero = (32767,32767), x_spacing = (2048,2048),y_spacing = (2048,2048)):
    x_value = x_axis_pin.value - zero[0]
    y_value = y_axis_pin.value - zero[1]
    if x_value >= 0:
        x_axis = x_value // x_spacing[1]
    else:
        x_axis = - ((-x_value) // x_spacing[0])
    if y_value >= 0:
        y_axis = y_value // y_spacing[1]
    else:
        y_axis = - ((-y_value) // y_spacing[0])
    return (x_axis,y_axis)
    
zero = get_zero(times =500, sleep = 0.01)
print(zero)
(x_extremum,y_extremum) = get_extremum(times = 500, sleep = 0.01)
print((x_extremum, y_extremum))
(x_spacing,y_spacing) = get_spacing(level = 128 , zero = zero, x_extremum = x_extremum,y_extremum = y_extremum)
print((x_spacing, y_spacing))

while True:
    coordinates = get_coordinates(zero = zero, x_spacing = x_spacing, y_spacing = y_spacing)
    print(coordinates)
    time.sleep(0.1)